1. Field of the Invention
Our invention pertains to the field of mechanical air moving, specifically to the ventilation of enclosed spaces, in this case a shower stall; it also pertains to the drying of surfaces by the action of a flowing layer of air.
2. Prior Art
A shower bath can add considerable heat and moisture to the air in a bathroom and ultimately in the entire building. This can result not only in fogged mirrors and wet walls in the bathroom, but also in a build-up of mold, mildew, and soap scum in the shower stall itself. In addition, the excess moisture in the air increases the latent heat load on the air conditioning system of the building.
This problem can be solved with adequate ventilation and drying. But while bathroom exhaust fans have long been in use, they are generally installed in the bathroom, somewhere outside the shower stall, in order to avoid code restrictions. Thus they do not arrest the warm, moist air before it escapes the shower stall, nor do they directly dry the inside surfaces of the shower stall. A device or system that does perform these functions should exhaust air directly from, and supply drying air directly to, the shower stall—preferrably by a reversal of air flow.
Air flow reversal methods have been proposed. An example is U.S. Pat. No. 4,250,917 to Knud Jesperson et al. (1981) of Canada. This apparatus was designed for processing meat, thousands of pounds at a time, and includes a large, complex enclosure with four dampers and a bank of heating and cooling coils. Another example is U.S. Pat. No. 4,521,517 to L. Paul Gauthier (1985), which is a large array of piping with five widely separated dampers designed for aerating compost piles. There is also U.S. Pat. No. 6,207,447 B1 to Mark Gould (2001), which again is a large system for aerating compost piles, with four dampers and a configuration not suited to a shower stall installation.
Moreover, a system that supplies drying air directly to the shower stall should include an air diffuser that distributes the air over the surfaces of the shower stall evenly, starting with the ceiling and moving downward. Such a diffuser should have a flat physical profile, that is, it should not project too far down from the ceiling. It should have some provision for adapting to various configurations of shower stalls and bathtub enclosures. It should also be attractive, clean looking, yet unobtrusive. Some form of plaque diffuser, (one with a flat air distribution plate) would be ideal for this application.
So far, we have found just one prior art patent relating to a plaque diffuser. This is U.S. Pat. No. 6,176,777 B1 to Smith et al. (2001). This diffuser comprises a square plaque set in a square, surrounding, outer “cone” and surmounted by a square inner cone that is movable for modulating the air flow. Temperature sensors in the air duct and room space send signals to a digital controller, which in turn sends signals to an actuator mechanism that moves the inner cone. This apparatus appears that it would be useful and beneficial for certain sophisticated air conditioning applications, but it is far too complex to be appropriate for a shower stall application.